The white powerball that is in the game was thought to have three colors:
blue, red and white.
The blue powerball was loaded to the autoplunger during tests of the
game, it was shot onto the playfield and
in the next second the bonus started counting down.
Due to the color of the ball nobody in the test team ever saw it on
the playfield!
Roger Sharpes´ (?) only comment was "Bad color"! The blue powerball
was only made in 4 examples or so, I don´t
know if they ever made a red powerball.
The two spiral magnets was originally three but the third was left out
due to economical reasons.
It was supposed to be placed just above the right spiral magnet (see
playfield art) and at the start of a regular
multiball the magnets should catch a ball each before releasing them
at the same time.
There are a few things that differs between early production games and
later ones. The early games has a rubber between
the left and lower bumper, the clock has a white clockface and the
"lock" arrow is green instead of yellow.
When the people at WMS shoved Rod Serlings´ widow Carol the prototype
backglass for her approval she only remarked
about one thing: the cigarette in Rods´ hand. So it was omitted
for the production backglass.
Twilight Zone is one the pinball games that is very popular to home
users, therefor has WMS made a special Game ROM
revision (9.4H) for the home players.
It has the usual set of rules plus a pause function, a cheat way to
get to the "Lost In The Zone" mode in no time and
software for the third spiral magnet (see above) if you have a sample
game.